Let the water flow: BC Hydro to flood John Hart generating station tunnels later this month

The John Hart Generating Station replacement project will soon turn on the taps and fill up the underground tunnels of the new underground hydroelectric generating facility on the Campbell River.

“It’s all culminating with this amazing ability for having waterflow starting this year,” said BC Hydro spokesperson Stephen Watson during a tour of the facility last week. “We’re going to have the water flowing into the tunnels end of March .”

That will be followed by two large water release valves taking over the flow of water into the Elk Falls canyon. Presently, the water is released through gates in the John Hart Dam. Two large water release valves will provide the water flow down Elk Falls Canyon.

The John Hart Generation Station replacement project is a $1.093 billion project replacing the 70-year-old John Hart Generating Station – which exists on the surface at the entrance to Elk Falls Canyon on the Campbell River – with a fully-underground facility built into the bedrock.

Water will actually be running through the tunnels by May and the first of the new turbines will be operating by June with the entire facility up and running by October. The project was initiated in 2007 and construction began in 2014.

“I’ve been fortunate enough to be involved in the project since it started in 2007. It’s been almost 11, 12 years in the making, when it’s all been said and done, and to see it happening like this, the challenges that the contractor has done a great job to overcome, it’s just a really exciting time for this community.”

Once completed, Watson said BC Hydro attains a facility that fulfills three goals: it’s seismically strong, embedded in bedrock; it protects downstream fish habitat by maintaining constant flows because of a bypass facility just to keep those flows going; and the power utility has a new generating facility that will last another 70 years.

“It’s extraordinarily impressive what’s been happening here for the last four years,” North Island MLA Claire Trevena said. “We’ve seen exponential growth from nothing through to a massive cavern to now where we have turbines in place, we have all the valves ready to go we’ve got the work completing.

“It’s been an extraordinary project.”

While turning on the taps is a nice metaphor, it’s not actually that simple. The process is done in stages (see diagram below):

Step 1: The water intake and valves:

First, water from the new intake at the dam will fill the water intake structure.

Second, with water from the intake structure, the two water release valves that will provide the water flow down Elk Falls Canyon will be commissioned.

Step 2: Tailrace and power tunnel:

To add water in tailrace tunnel, BC Hydro will pull the metal stop logs at the tunnel outlet and slowly allow water to enter the tunnel. This may take a day.

To fill the power tunnel, the large operating gate within the water intake structure will be opened in stages. There are seven steps for watering up the power tunnel and it may take two weeks to complete.

Step 3: Start commissioning/wet testing:

Once all the water is in, Hydro will begin preparing for operation of the generators and water bypass facility.

InPower BC CEO Paul Sawyer (left) discusses the water release valves with North Island MLA CLaire Trevena. The John Hart Dam is the concrete structure to the right. Photo by Alistair Taylor/Campbell River Mirror